PROJECT SUMMARY Callous-unemotional (CU) traits (e.g., lack of guilt or remorse, low empathy, shallow affect) are consistent with the core affective features of adult psychopathy and are an established risk factor for early emerging, persistent, and severe youth misconduct. CU traits reflect impairment in identified neurocognitive mechanisms that interfere with child socialization and predict poorer treatment outcomes, even with well-established treatments for disruptive behavior, and thus call for novel interventions. Prominent theories that attempt to account for the failure of those with CU traits to recognize, and respond appropriately to, others' emotional distress all emphasize fundamental deficits in affect sensitivity, including reduced attention toward and recognition of others emotional cues, particularly signals of distress (e.g., facial expressions of fear, sadness). On the other hand, high-CU youth show normal to exaggerated reward responsivity. We assert that impaired sensitivity for emotional distress cues (fear and/or sadness) is mechanistically linked to CU traits in children, and that by targeting facial affect sensitivity (FAS) directly via a computerized automated feedback and incentive system, we can exert downstream effects on CU traits. We thus propose an experimental therapeutics approach to develop and test a novel neurocognitive intervention for CU traits. The first phase (R61) of the proposed project will demonstrate, in a preliminary randomized controlled trial (RCT; N=30), that a new neurocognitive intervention (Facial Affect Sensitivity Training: FAST) can engage the target, FAS (measured primarily by FER accuracy for distress expressions, and secondarily by heightened eye gaze and neural activity) in children with elevated CU traits. We will examine individual growth rates and test slope differences between conditions (FAST v control). Target engagement will be defined as medium effect size (d > .40) in the comparison of FAST vs. no- treatment control on the primary target (distress FER). We will also aim to determine optimal dose parameters with regard to number of sessions for FER improvement (e.g., timing of local bump or decay, amount of change, when maximal change occurs), and participant satisfaction with session frequency, length, and number. In the R33 phase, we aim to replicate target engagement with a new, larger high-CU sample, and evaluate feasibility and preliminary efficacy of FAST, in the context of an RCT (N = 50) in which FAST is compared to an active control condition (ACC; implicit eye gaze training), including examining downstream change in CU traits. If the FAST intervention improves FER and reduces CU traits, such training in early childhood could help interrupt the developmental cascade toward antisocial outcomes.